<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>05_流程控制</title>
</head>
<body>
<script>
    // 1.顺序节构
    console.log(1);
    console.log(2);
    console.log(3);


    //2.分支结构
    let username = ' ';
    if(!username){
        alert('用户名不能为空!');
    }else{
        alert('欢迎'+username+'回归！')
    }
    //3.选择分支
    let gender = 10;
    switch (gender){
        case 1:
            console.log('男');
            break;
        case 2:
            console.log('女');
            break;
        default:
            console.log('未知');
    }
    //4.循环结构
    let names = ['张三','李四','王五','赵六','钱七'];
    for (let i = 0; i < names.length; i++){
        console.log(names[i])
    }
    for(let n of names){
        console.log(n);
    }
</script>
</body>
</html>